In New Orleans, where more than 2,000 people were infected, travel was not significantly reduced until March 20, weeks after Mardi Gras had gathered huge crowds. In Albany, Georgia, a city of 75,000, travel reductions in the past few weeks were too late to stop a group of illnesses apparently started after a funeral in late February. Travel started to decline only about two weeks ago in Indianapolis, Chicago, Miami and Phoenix, giving way to continued growth last month.